Simplify the following expression: $ p = \dfrac{-q}{q - 2} - \dfrac{-3}{7} $
Explanation: In order to subtract expressions, they must have a common denominator. Multiply the first expression by $\dfrac{7}{7}$ $ \dfrac{-q}{q - 2} \times \dfrac{7}{7} = \dfrac{-7q}{7q - 14} $ Multiply the second expression by $\dfrac{q - 2}{q - 2}$ $ \dfrac{-3}{7} \times \dfrac{q - 2}{q - 2} = \dfrac{-3q + 6}{7q - 14} $ Therefore $ p = \dfrac{-7q}{7q - 14} - \dfrac{-3q + 6}{7q - 14} $ Now the expressions have the same denominator we can simply subtract the numerators: $p = \dfrac{-7q - (-3q + 6) }{7q - 14} $ Distribute the negative sign: $p = \dfrac{-7q + 3q - 6}{7q - 14}$ $p = \dfrac{-4q - 6}{7q - 14}$